One of the most common heart diseases is atherosclerotic cardiovascular disease, caused by the buildup of lesions or plaque on the inside wall of blood vessels. For example, a variety of lesions may occur related to atherosclerosis, including aorto-ostial lesions. Aorto-ostial lesions damage the ostium of the main blood vessels branching from the aorta. This can result in a partial, or even complete, blockage of the artery. As a result of the danger associated with such a blockage, several methods and procedures have been developed to treat arterial blockages.
One such method is an angioplasty procedure which uses an inflatable balloon to dilate the blocked artery. Angioplasty procedure involves the use of a dilatation balloon catheter. The balloon catheter is advanced, using fluoroscopy, over a guidewire so that the balloon is positioned adjacent a stenotic lesion. The balloon is then inflated inside a stenosed region in a blood vessel in order to apply radial pressure to the inner wall of the vessel and widen the stenosed region to enable better blood flow.
The efficacy of the dilation of a stenosis can be enhanced by incising the material that creates the stenosis. Consequently, angioplasty balloons with scoring elements, such us cutting edges, atherotomes or blades mounted on the surface of the balloon were proposed, which are intended to incise a stenosis during the dilation procedure. The cutting balloons can also be used to break through or scrape plaque and stenoses.
For example, U.S. Pat. No. 5,196,024 to Barath et al. describes a device and method for dilation or recanalization of a diseased vessel by use of a balloon catheter with cutting edges to make longitudinal cuts in the vessel wall. The diameter of the vessel can be increased without subsequent secondary cellular proliferation or restenosis in the vessel caused by angioplasty methods.
U.S. Pat. Pub. No. 2004243156A to Show-men et al. and U.S. Pat. No. 7,291,158 to Bence et al. describe various angioplasty balloon catheters and methods of making and using the same. The balloon catheters include a catheter shaft and a balloon coupled to the shaft. The balloon catheters include one or more cutting edges, blades or wings coupled to the balloon.
One of the drawbacks of the prior art cutting balloons equipped with cutting edges or blades is associated with the fact that these devices tend to be fairly stiff. This has the affect of limiting the flexibility and deliverability of the balloon as it is advanced through the tortuous confines of a vessel or other body lumens. Moreover, the cutting balloons equipped with cutting blades and edges can be difficult to deflate and collapse. This can make removal of the balloons from the vasculature more difficult than the removal of corresponding angioplasty balloons which do not include stiff cutting blades. Additionally, it was found that the cuts imparted by such cutting balloons do not always provide the dilatation and treatment of fibrotic lesions as would be desired.
Angioplastic balloons that employ a woven mesh, cutting strings or wires are also known. These balloons are proved to be more flexible and safer than the balloons employing cutting blades and edges.
For example, U.S. Pat. Pub. No. 2006/259005A describes an angioplasty dilatation device provided with scoring elements which may incorporate a drug to be delivered to a body lumen, typically a blood vessel. The scoring elements can, for example, be in the form of a single wire or a plurality of wires wrapped around a dilatation balloon in a helical configuration.
U.S. Pat. Pub. No. 2007/198047A describes a cutting balloon catheter assembly including a catheter equipped with an inflatable balloon having an interior cavity and an expandable covering disposed about the balloon. The expandable covering is in the form of a mesh coating having a cross-hatched pattern. The mesh coating is made of plastic or metal fibers, where some of the fibers have cutting edges. In operation, the cutting edges abrade the stenoses, plaque or lesions along the vessel walls, when the catheter assembly is reciprocally moved longitudinally or rotationally after inflation of the balloon.
A coronary stenting procedure is known in the art for treatment of aorto-ostial lesions. An incomplete apposition between the stent filaments and the arterial wall can increase the risk of an embolic source as a result of the stagnation of the blood flow in the dead space. A strong compression of the vessel wall on the opposite side of the unattachment at the stent edge because of the straightening effect on tortuous vascular curves may induce a kink in the artery that thus could possibly cause edge restenosis. It is also recognized in the art that incomplete expansion of the stent as compared with a predefined reference (stent underexpansion) can result in calcification, which significantly increases the subsequent risks of restenosis and/or stent thrombosis.
Systems and methods are known that provide stent visualization in coronary arteries, and provide analysis tools based on enhanced angiograms (of the deployed stent). Such analysis can provide information on the success of the stent deployment. Based on the enhanced image the physician can decide whether the procedure was carried out satisfactory or might also decide to further dilate or deploy another stent. The shortcoming of all those systems and methods is that they are providing information only after stent deployment.